JP2019181627A - Wrist structure of robot - Google Patents

Abstract

To facilitate installation or maintenance of a driving motor and a filament body.SOLUTION: A wrist structure 1 of a robot comprises a first wrist element 2, a second wrist element 3 and a third wrist element 4, in which the first wrist element 2 comprises a casing 5 of a hollow structure, two driving motors 6 and 7 stored in its inside space and driving the second wrist element 3 and the third wrist element 4 and a conduit member 9 for passing a filament body in the direction along the first axis A up to the second wrist element 3 side from the arm 140 side in the inside space, and a first sidewall 10 and a second sidewall 11 positioned on both sides for sandwiching a reference plane F are provided with a first opening part and a second opening part, and the first opening part has a size capable of passing the driving motors 6 and 7, and the center of rotary shafts D and E of the two driving motors 6 and 7 is arranged between the first sidewall 10 and the reference plane F, and the conduit member 9 is arranged between the second sidewall 11 and the driving motors 6 and 7, and the filament body is arranged in a curved passage for bypassing the driving motors 6 and 7.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wrist structure of a robot.

2. Description of the Related Art Conventionally, a wrist structure that is attached to the tip of a robot arm is known that incorporates a drive motor for two axes at the tip and a conduit member for the striatum for guiding the striatum from the arm to the wrist tip. (For example, refer to Patent Document 1).
In the wrist structure of Patent Document 1, a conduit member is disposed straight along an axis for rotating the wrist relative to the arm, and two drive motors are disposed at positions sandwiching the conduit member.

Japanese Patent No. 5833836

  However, since the conduit member is sandwiched between the two drive motors in the wrist structure of Patent Document 1, the conduit member cannot be accessed unless one of the drive motors is removed. Is inconvenient.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a wrist structure for a robot that can facilitate mounting or maintenance of a drive motor and a linear body.

  One aspect of the present invention includes a first wrist element rotatably supported around the first axis at the tip of a robot arm, and a second axis that intersects the first axis at the tip of the first wrist element. A second wrist element rotatably supported; and a third wrist element rotatably supported around a third axis intersecting the second axis at a tip of the second wrist element, the first wrist The element has a hollow casing, two drive motors housed in the internal space of the casing and driving the second wrist element and the third wrist element, and the second space from the arm side in the internal space. A first side wall located on both sides of a plane including the first axis and the second axis of the casing, and a conduit member that passes a linear body in a direction along the first axis to the wrist element side; On the second side wall, the internal space The first opening and the second opening are provided to open to the outside, and the first opening has a size capable of passing through the drive motor, and the rotation shaft centers of the two drive motors are the first The robot is disposed between one side wall and the plane, and the conduit member is disposed between the second side wall and the drive motor, and the linear member is disposed on a curved path that bypasses the drive motor. The wrist structure.

  According to this aspect, two drive motors can be accommodated in the internal space of the casing from the outside via the first opening provided in the first side wall. In this case, two drive motors are attached to the casing at a position where the rotation shaft is disposed between the plane including the first axis and the second axis and the first side wall. Thereby, in the internal space of a casing, since a drive motor is biased and arrange | positioned at the 1st side wall side, a space is formed between a drive motor and a 2nd side wall. And a conduit member can be arrange | positioned in the formed space.

  A linear member extending along the first axis from the arm side into the internal space to the second wrist element side is disposed in a curved path that bypasses the two drive motors by passing through the conduit member. Is done. That is, in the vicinity of the connection position between the arm and the first wrist element that rotates about the first axis with respect to the arm, it is preferable that the striate passes through the vicinity of the first axis that is the center of rotation. In the vicinity of the second wrist element that rotates relative to the second wrist element, it is preferable to pass through the vicinity of the first axis that is the center of the rotation angle range of the second wrist element. In the vicinity of the center of the internal space, even if the drive motor is detoured through a path away from the first axis, the burden on the striatum is small.

  According to this aspect, the workability at the time of mounting or replacing the drive motor via the first opening provided in the first side wall can be improved by bringing the drive motor close to the first side wall. In addition, by bringing the conduit member close to the second side wall, it is possible to mount or maintain the striate body via the second opening provided in the second side wall without removing the drive motor. Can be improved. Furthermore, since the conduit member is disposed between the second side wall and the drive motor, the linear body does not contact the second side wall, and the linear body does not protrude outside the second side wall. Thereby, it is possible to suppress the interference to the peripheral device due to the protrusion of the striate body, and to perform off-line teaching more easily.

In the said aspect, a part of said drive motor may be arrange | positioned between the said plane and the said 2nd side wall.
This configuration suppresses the protrusion height of the drive motor from the plane as compared to the case where the entire drive motor is disposed in the space between the plane including the first axis and the second axis and the first side wall. Can do. As a result, the casing can also be reduced in size by suppressing the protruding height from the plane, and the interference radius of the first wrist element around the first axis can be reduced.

Moreover, in the said aspect, the center vicinity of the said internal space may be contained in the area | region pinched by the two said drive motors and two these drive motors.
With this configuration, when the drive motor is disposed near the center of the internal space, the conduit member is also disposed near the center. Thereby, in the vicinity of the center of the internal space, even if the drive motor is detoured through a path away from the first axis, it is possible to reduce the burden on the striatum.

Moreover, in the said aspect, at least one part of two said drive motors may be arrange | positioned overlapping in the said 1st axis direction.
With this configuration, the positions of the two drive motors in the first axis direction can be shortened. Thereby, since the area where a linear body detours a drive motor through the path | route which leaves | separates from a 1st axis line becomes small, the burden concerning a linear body can be reduced. Moreover, since the 1st opening part provided in the 1st side wall can be made small, the rigidity fall of a casing can be suppressed.

In the above aspect, the casing may rotatably support the second wrist element on both sides in the second axial direction.
With this configuration, the second wrist element can be supported with high rigidity by the double-supported structure with respect to the first wrist element.

Further, in the above aspect, a third side wall and a fourth side wall located on both sides in the second axial direction of the casing, a mounting surface for attaching any of the drive motors, and a through hole that penetrates the rotating shaft, An opening for processing for processing the mounting surface may be provided at a position facing the mounting surface.
With this configuration, it is possible to attach the drive motor to the mounting surface by allowing the rotation shafts of the two drive motors accommodated in the internal space to pass through the through holes provided in the third side wall and the fourth side wall. By processing each mounting surface from a processing opening that is open at a position facing the mounting surface, the casing can be formed of a single component. Since the opening for processing has a minimum size necessary for processing, the opening area can be minimized and the rigidity of the casing can be prevented from being lowered.

Further, since the two drive motors can be accommodated in the internal space of the casing from the outside via the first opening provided in the first side wall from the outside, the machining opening can pass through the drive motor. It doesn't have to be big. Thereby, the position of the two drive motors in the first axis direction can be made shorter than in the case where the machining opening is large enough to pass through the drive motor.
In addition, by disposing at least a part of the drive motor in the first axial direction, the first opening provided in the first side wall is made small, the rigidity of the casing is suppressed, and the conduit member is downsized. can do.

  In the above aspect, a pulley for rotating a belt for driving the second wrist element or the third wrist element is fixed to the rotation shaft of at least one of the drive motors, and the drive motor is The position can be adjusted in the direction in which the tension applied to the belt is changed along the mounting surface, and the driving motor is adjusted for position adjustment through the machining opening formed on the same side wall as the mounting surface. You may provide the interface which can attach a tool.

  With this configuration, the position adjusting jig is attached to the interface provided in the drive motor via the machining opening, and the tension applied to the belt that is turned around the pulley is moved by moving the drive motor along the attachment surface. Can be adjusted.

  According to the present invention, there is an effect that the mounting or maintenance of the drive motor and the linear body can be facilitated.

It is a perspective view which shows the robot provided with the wrist structure which concerns on one Embodiment of this invention. It is a figure which shows the wrist structure of FIG. It is a longitudinal cross-sectional view which shows the wrist structure of FIG. It is the longitudinal cross-sectional view which cut | disconnected the wrist structure of FIG. 1 along the reference plane. It is the figure which removed the cover and looked at the wrist structure of FIG. 2 from the back side. It is the figure which removed the cover of the wrist structure of FIG. It is a perspective view which shows the 1st casing of the wrist structure of FIG. It is the perspective view which looked at the 1st casing of Drawing 7 from a different direction. It is the partial figure which looked at the 2nd arm of the robot of Drawing 1 from the back side. It is a longitudinal cross-sectional view which shows the path | route of the filament within the internal space of the wrist structure of FIG. FIG. 4 is a cross-sectional view showing the positional relationship between a drive motor and a conduit member in the internal space of the wrist structure of FIG. 3. It is a front view of the wrist structure of FIG. It is a perspective view which shows the state which attached the adapter to the drive motor for the 2nd wrist element drive with which the wrist structure of FIG. 1 is equipped. It is a perspective view which shows the state which attached the adapter to the drive motor for a 3rd wrist element drive with which the wrist structure of FIG. 1 is equipped. It is a side view which shows the interface of the adapter for 2nd wrist elements exposed to the opening part for a process of the wrist structure of FIG. It is a side view which shows the interface of the adapter for 3rd wrist elements exposed to the opening part for a process of the wrist structure of FIG. It is a figure explaining the tension | tensile_strength adjustment work of the belt which attached the jig for position adjustment to the interface of FIG. It is a figure explaining the tension | tensile_strength adjustment operation | work of the belt which attached the jig for position adjustment to the interface of FIG.

A wrist structure 1 of a robot 100 according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the robot 100 including the wrist structure 1 according to the present embodiment is, for example, a 6-axis articulated robot, and includes a base 110 installed on the ground and a base 110 around a vertical axis. , A first arm 130 that swings with respect to the swing drum 120 about a horizontal axis, and a second arm (arm) 140 that swings with respect to the first arm 130 about a horizontal axis. And a wrist unit (wrist structure) 1 attached to the tip of the second arm 140.

  As shown in FIG. 2, the wrist unit 1 includes a first wrist element 2 that is rotatably supported about the first axis A with respect to the second arm 140, and a second axis B that is orthogonal to the first axis A. The second wrist element 3 supported so as to be rotatable with respect to the first wrist element 2 and the third axis C around the second axis B and passing through the intersection of the first axis A and the second axis B And a third wrist element 4 supported rotatably with respect to the second wrist element 3.

As shown in FIG. 3, the first wrist element 2 includes a hollow first casing (casing) 5, two drive motors 6 and 7 housed in the internal space of the first casing 5, and an internal space And a conduit member 9 through which a linear member (see FIG. 10) 8 passes.
As shown in FIG. 3, the first casing 5 includes a first side wall 10 and a second side disposed on both sides of a plane including the first axis A and the second axis B (hereinafter referred to as a reference plane F). As shown in FIG. 4, the side wall 11, the third side wall 12 and the fourth side wall 13 located on both sides in the second axis B direction, and the side wall 11 located on both sides in the first axis A direction as shown in FIG. 3. A box-like single part having a fifth side wall 14 and a sixth side wall 15 that define an internal space surrounded by the six side walls 10, 11, 12, 13, 14, 15. .

  As shown in FIG. 5, the first side wall 10 is provided with a first opening 16 that opens the internal space to the outside. Moreover, the 2nd opening part 17 which opens internal space outside is provided in the 2nd side wall 11 as FIG. 6 shows. The first opening 16 has a size that allows the drive motors 6 and 7 to pass therethrough. Each of the first opening 16 and the second opening 17 is closed by a removable cover 18 as shown in FIG.

As shown in FIG. 2, the third side wall 12 and the fourth side wall 13 are partially extended from the sixth side wall 15 toward the distal end side to form a bifurcated shape, and the second wrist inserted between them. The element 3 is rotatably supported on both sides in the second axis B direction. Thereby, the 2nd wrist element 3 is supported with high rigidity with respect to the 1st casing 5 by the both-ends support structure.
As shown in FIGS. 7 and 8, the third side wall 12 and the fourth side wall 13 have through holes 19 through which the rotation shafts D and E of the drive motors 6 and 7 penetrate from the inner space side of the first casing 5. 20 and mounting surfaces 21 and 22 of the drive motors 6 and 7 formed on inner surfaces around the through holes 19 and 20, respectively.

  The through holes 19 and 20 and the mounting surfaces 21 and 22 of the third side wall 12 and the fourth side wall 13 are opposite to each other with the rotation axes D and E of the two drive motors 6 and 7 in parallel as shown in FIG. And is provided at a position to be mounted in parallel in the first axis A direction. That is, the through holes 19 and 20 and the mounting surfaces 21 and 22 of the third side wall 12 and the fourth side wall 13 are arranged at positions shifted in the first axis A direction as shown in FIGS. .

Further, as shown in FIG. 7, the third side wall 12 has a processing opening 23 for processing the mounting surface 22 on the inner surface of the fourth side wall 13 on the mounting surface 22 of the fourth side wall 13. It is provided at a position facing the direction. As shown in FIG. 8, the fourth side wall 13 has a processing opening 24 for processing the mounting surface 21 on the inner surface of the third side wall 12 in the second axis B direction on the mounting surface 21 of the third side wall 12. It is provided at an opposing position. Thereby, the through hole 19 and the processing opening 23 of the third side wall 12 are arranged side by side in the direction along the first axis A, and the through hole 20 of the fourth side wall 13 and the processing opening 24 are the first. They are arranged side by side in the direction along the axis A.
As shown in FIGS. 2 and 4, covers 25 and 26 for defining a space for accommodating a power transmission mechanism 34 described later are detachably attached to the outside of the third side wall 12 and the fourth side wall 13. .

  Further, the attachment surfaces 21 and 22 of the third side wall 12 and the fourth side wall 13 are provided at positions shifted to the first side wall 10 side with respect to the reference plane F. Thus, the drive motors 6 and 7 attached to the attachment surfaces 21 and 22 are arranged such that the centers of the rotation axes D and E are disposed between the reference plane F and the first side wall 10 as shown in FIG. Yes. The drive motors 6 and 7 are not entirely disposed between the reference plane F and the first side wall 10, but a part of the drive motors 6 and 7 protrudes into the space of the second side wall 11 from the reference plane F. Has been placed.

  In the internal space of the first casing 5, the two drive motors 6, 7 are arranged at positions shifted toward the first side wall 10, so that a space is created between the drive motors 6, 7 and the second side wall 11. The conduit member 9 is arranged in the internal space using this space.

  Specifically, as shown in FIG. 3, the conduit member 9 is formed in a straight tube shape, and its longitudinal axis is parallel to the first axis A, and between the drive motors 6 and 7 and the second side wall 11. It is fixed in space. The distal end side of the conduit member 9 extends toward the distal end. The conduit member 9 is made of, for example, a material having a small friction coefficient such as resin. Alternatively, a metal inner surface with a liner or coating made of a material having a small friction coefficient may be employed.

  The linear member 8 that penetrates into the conduit member 9 is an elastic cable that can be elastically deformed, such as an electric cable that supplies power to a tool attached to the third wrist element 4, a pipe that supplies fluid, or a welding wire. A member can be mentioned.

  The fifth side wall 14 is formed in a circular shape as shown in FIG. 8, and is fixed to the output shaft of the speed reducer 150 fixed to the second arm 140, as shown in FIG. As shown in FIGS. 3 and 9, the second arm 140 and the speed reducer 150 have a hollow that penetrates straight from the back side of the second arm 140 around the first axis A along the first axis A. A portion 160 is formed. In FIG. 3, reference numeral 170 denotes a drive motor that supplies a drive force for rotating the first wrist element 2 about the first axis A to the speed reducer 150. As shown in FIG. 8, the fifth side wall 14 is provided with a through hole 27 that is connected to the hollow portion 160 of the speed reducer 150 around the first axis A. Further, as shown in FIG. 7, the sixth side wall 15 is also provided with a through hole 28 around the first axis A.

  As shown in FIG. 10, the second arm 140 enters the internal space of the first casing 5 via the hollow portion 160 and the through hole 27 of the fifth side wall 14 from the back side of the second arm 140, and the through hole of the sixth side wall 15. The intermediate position of the linear body 8 extending along the first axis A by arranging the intermediate position in the longitudinal direction of the linear body 8 guided to the second wrist element 3 side via 28 in the conduit member 9. Are arranged along a curved path that bypasses the drive motors 6 and 7.

  As shown in FIG. 11, the conduit member 9 can be radially divided into two along a parting line parallel to the reference plane F by removing the bolt. Thereby, by dividing the conduit member 9 via the second opening 17, the linear member 8 penetrating through the conduit member 9 can be easily accessed from the second opening 17.

  As shown in FIG. 4, the second wrist element 3 is supported by a double-supported structure so as to be rotatable about the second axis B with respect to the first casing 5 by a speed reducer 29 and a bearing 30. 31 is provided. A speed reducer 32 constituting the third wrist element 4 is fixed to the tip of the second casing 31. The second casing 31 and the speed reducer 32 are provided with a through hole 33 penetrating along the third axis C. The linear body 8 that has come out of the internal space of the first casing 5 via the through hole 28 of the sixth side wall 15 can be passed through the through hole 33 provided in the second casing 31 and the speed reducer 32, A tool (not shown) attached to the tip of the three wrist element 4 can be guided.

  As shown in FIG. 4, between the two drive motors 6, 7 accommodated in the internal space of the first casing 5 and the second wrist element 3 and the third wrist element 4, the drive motor 6, Power transmission mechanisms 34 and 41 for transmitting power from 7 are provided.

A power transmission mechanism 34 that transmits power to the second wrist element 3 includes a shaft 35 that is rotatably supported around the second axis B by a bearing 30 on the third side wall 12 of the first casing 5, and a drive motor 7. A pulley 36 fixed to the rotary shaft E, a pulley 37 fixed to the shaft 35, and a belt 38 spanned between the pulleys 36, 37. A gear 40 that meshes with the input shaft gear 39 of the speed reducer 29 is provided at the tip of the shaft 35.
Thus, the power of the drive motor 7 is transmitted to the shaft 35 via the pulleys 36, 37 and the belt 38, and the input shaft gear 39 of the speed reducer 29 is rotated by the rotation of the shaft 35, whereby the second wrist. The element 3 is rotated around the second axis B.

  A power transmission mechanism 41 that transmits power to the third wrist element 4 includes a first shaft 43 that is supported on the fourth side wall 13 of the first casing 5 by a bearing 42 so as to be rotatable about the second axis B, and a first shaft 43. A first gear 44 provided on the shaft 43, a second shaft 45 instructed by the bearing 42 to be rotatable about an axis parallel to the third axis C by the bearing 42, and provided at one end of the second shaft 45 The second gear 46 that meshes with the first gear 44, the third gear 48 that is provided at the other end of the second shaft 45 and meshes with the input shaft gear 47 of the speed reducer 32, and the rotation shaft D of the drive motor 6. A pulley 49, a pulley 50 fixed to the first shaft 43, and a belt 51 spanned between the pulleys 49, 50 are provided.

  Thereby, the power of the drive motor 6 is transmitted to the first shaft 43 via the pulleys 49 and 50 and the belt 51, and is transmitted to the second shaft 45 by the meshing of the first gear 44 and the second gear 46, When the input shaft gear 47 of the speed reducer 32 is rotated by the rotation of the second shaft 45, the output shaft of the speed reducer 32 that is the third wrist element 4 is rotated around the third axis C.

An operation of the wrist structure 1 of the robot 100 according to the present embodiment configured as described above will be described below.
According to the wrist structure 1 of the robot 100 according to the present embodiment, the drive motors 6 and 7 are arranged at positions shifted toward the first side wall 10 from the central reference plane F in the internal space of the first casing 5. Therefore, it is close to the first opening 16 provided in the first side wall 10, and the drive motors 6 and 7 are inserted into and attached to the internal space of the first casing 5 via the first opening 16. There is an advantage that the drive motors 6 and 7 can be easily taken out from the internal space.

  Further, as a result of arranging the drive motors 6 and 7 so as to be biased toward the first side wall 10, the linear member 8 can be arranged in a space between the drive motors 6 and 7 and the second side wall 11. That is, it is possible to directly access the linear body 8 disposed in the internal space of the first casing 5 via the second opening 17 provided in the second side wall 11, and to attach or replace the linear body 8. There is an advantage that the maintenance work such as the above can be easily performed without removing the drive motors 6 and 7. Further, since the conduit member 9 is fixed in the space between the drive motors 6 and 7 and the second side wall 11, the linear body 8 does not contact the second side wall 11, and the linear body 8 is the second. It does not protrude outside the side wall 11. Thereby, the interference to the peripheral device due to the protrusion of the filament 8 can be suppressed, and the off-line teaching can be executed more easily.

Further, the linear member 8 that crosses the internal space of the first casing 5 in the direction along the first axis A from the through hole 27 of the fifth side wall 14 of the first casing 5 to the through hole 28 of the sixth side wall 15 is A curved path that bypasses the drive motors 6 and 7 is traced at a midway position. By biasing the drive motors 6 and 7 toward the first side wall 10 side, as shown in FIG. It ’s enough.
At the connecting position of the first wrist element 2 that rotates around the first axis A and the second arm 140, the linear member 8 is displaced along with the rotation, but is rotated by being passed through the vicinity of the first axis A. This eliminates the heavy load caused by Also, at the position of the sixth side wall 15 from the first casing 5 toward the second wrist element 3, the striate body 8 is curved along with the rotation of the second wrist element 3 around the second axis B, By allowing the through hole 28 in the vicinity of the one axis A to pass, the load applied to the filament 8 is evenly distributed.

  Then, by gently curving the linear body 8 in the internal space of the first casing 5, the linear body 8 acts on the linear body 8 when the first wrist element 2 rotates about the first axis A relative to the second arm 140. There is an advantage that the load applied to the wire body 8 can be further reduced by effectively absorbing the twist.

  In the present embodiment, in the internal space of the first casing 5, the entire drive motors 6 and 7 are not disposed on the first side wall 10 side of the reference plane F, but a part of the drive motors 6 and 7 is disposed. As shown in FIG. 12, compared with the case where the entire drive motors 6 and 7 are arranged on the first side wall 10 side with respect to the reference plane F because they are projected on the second side wall 11 side with respect to the reference plane F. As a result, there is an advantage that the height of the first casing 5 on both sides from the reference plane F can be reduced, and the wrist interference radius R which is the maximum rotation radius around the first axis A can be reduced.

  In the present embodiment, the tool is inserted into the internal space of the first casing 5 via the processing opening 23 of the third side wall 12 (or the fourth side wall 13), and the fourth side wall 13 (or the third side wall 13). Since the mounting surface 22 is processed on the inner surface of the side wall 12), the first casing 5 can be manufactured as a single part without being divided. Thereby, the number of parts can be reduced and rigidity can be improved. Further, the processing openings 23 and 24 do not need to be large enough to pass through the drive motors 6 and 7, and have two drives compared to the case where the openings are large enough to pass through the drive motors 6 and 7. The positions of the motors 6 and 7 in the first axis A direction can be further shortened. Further, the processing openings 23 and 24 need only be the minimum size required for processing, and can be suppressed to be smaller than the size of the mounting surfaces 21 and 22 to prevent the rigidity of the first casing 5 from being lowered. it can.

In the present embodiment, pulleys 36, 37, 49, 50 and belts are used as the power transmission mechanisms 34, 41 for transmitting the power for driving the second wrist element 3 and the third wrist element 4 from the drive motors 6, 7. Although the thing provided with 38,51 was illustrated, you may employ | adopt other arbitrary power transmission mechanisms, such as a gearwheel, without limiting to this.
When a power transmission mechanism 34, 41 having pulleys 36, 37, 49, 50 and belts 38, 51 is employed, it is necessary to adjust the tension of the belts 38, 51.

  For example, adapters 52 and 53 are attached to the drive motors 6 and 7, as shown in FIGS. The mounting surfaces 21 and 22 of the first casing 5 are provided with long holes extending in the first axis A direction, and the adapters 52 and 53 are provided with screw holes 54 and 55 for fastening bolts penetrating the long holes. . Further, as shown in FIGS. 15 and 16, the adapters 52 and 53 are exposed from the processing openings 23 and 24 when the drive motors 6 and 7 with the adapters 52 and 53 are attached to the first casing 5. Interfaces 56 and 57 are provided. The interfaces 56 and 57 have two or more screw holes 58 and 59, and the position adjusting jigs 60 and 61 can be fixed to the adapters 52 and 53 via the processing openings 23 and 24. .

  The position adjusting jigs 60 and 61 are L-shaped blocks that are fixed to the interfaces 56 and 57 of the adapters 52 and 53 by bolts as shown in FIGS. 17 and 18, for example. Bolts 62 and 63 are supported in screw holes extending in a direction parallel to A. The screw holes are arranged at positions where the inner surfaces of the processing openings 23 and 24 coincide with the extension lines of the screw holes in a state where the position adjusting jigs 60 and 61 are attached to the adapters 52 and 53. By tightening the bolts 62 and 63 fastened to the screw holes, the inner surfaces of the processing openings 23 and 24 are pushed by the tips of the bolts 62 and 63, and the adapters 52 and 53 are moved in the direction of the reaction force. Thus, the tension of the belts 38 and 51 can be adjusted.

  In the present embodiment, it is preferable that the area between the two drive motors 6 and 7 and the two drive motors 6 and 7 includes the vicinity of the center of the internal space. Further, in the vicinity of the connection position of the second arm 140 and the first wrist element 2 that rotates around the first axis A with respect to the second arm 140, the vicinity of the first axis A where the linear member 8 is the rotation center. More preferably, it passes through. Further, in the vicinity of the second wrist element 3 that rotates relative to the first wrist element 2, it is more preferable that the vicinity of the first axis A that is the center of the rotation angle range of the second wrist element 3 is passed.

  Thus, when the drive motors 6 and 7 are arranged in the vicinity of the center of the internal space, the conduit member 9 is also arranged in the vicinity of the center, and in the vicinity of the center of the internal space, the path from which the filament 8 is separated from the first axis A. Even if the drive motors 6 and 7 are detoured through, the burden on the filament 8 can be reduced.

In the present embodiment, at least a part of the two drive motors 6 and 7 may be arranged so as to overlap in the first axis A direction.
Thereby, the position of the two drive motors 6 and 7 in the first axis A direction can be shortened. In addition, since the section in which the linear body 8 bypasses the drive motors 6 and 7 through the path away from the first axis A is reduced, the burden on the linear body 8 can be reduced. Furthermore, the 1st opening part 16 provided in the 1st side wall 10 can be made small, the rigidity fall of the 1st casing 5 can be suppressed, and the conduit member 9 can be reduced in size.

1 Wrist unit (wrist structure)
2 1st wrist element 3 2nd wrist element 4 3rd wrist element 5 1st casing (casing)
6, 7 Drive motor 8 Linear body 9 Conduit member 10 1st side wall 11 2nd side wall 12 3rd side wall 13 4th side wall 16 1st opening part 17 2nd opening part 19 and 20 Through-hole 21 and 22 Mounting surface 23, 24 Processing opening 36, 37, 49, 50 Pulley 38, 51 Belt 56, 57 Interface 100 Robot 60, 61 Position adjustment jig 140 Second arm (arm)
A 1st axis B 2nd axis C 3rd axis D, E Rotation axis F Reference plane

Claims (7)

A first wrist element supported at the tip of a robot arm so as to be rotatable about a first axis;
A second wrist element rotatably supported around a second axis intersecting the first axis at the tip of the first wrist element;
A third wrist element rotatably supported around a third axis intersecting the second axis at the tip of the second wrist element;
The first wrist element includes a hollow casing, two drive motors that are housed in an internal space of the casing and drive the second wrist element and the third wrist element, and the arm side in the internal space. A conduit member that passes the filament in a direction along the first axis from the second wrist element side to the second wrist element side,
A first opening and a second opening for opening the internal space to the outside are provided on first and second side walls located on both sides of a plane including the first axis and the second axis of the casing. And
The first opening has a size capable of passing through the drive motor;
The rotational axis centers of the two drive motors are disposed between the first side wall and the plane;
A wrist structure of a robot, wherein the conduit member is disposed between the second side wall and the drive motor, and the linear member is disposed in a curved path that bypasses the drive motor.   The wrist structure of the robot according to claim 1, wherein a part of the drive motor is disposed between the plane and the second side wall.   The wrist structure of the robot according to claim 1 or 2, wherein a region near the center of the internal space is included in an area between the two drive motors and the two drive motors.   The wrist structure of the robot according to any one of claims 1 to 3, wherein at least a part of the two drive motors are arranged so as to overlap in the first axis direction.   The robot wrist structure according to claim 1, wherein the casing rotatably supports the second wrist element on both sides in the second axial direction.   A mounting surface to which any one of the drive motors is attached to a third side wall and a fourth side wall located on both sides of the casing in the second axial direction, a through hole through which the rotary shaft passes, and a position facing the mounting surface A wrist structure for a robot according to any one of claims 1 to 5, further comprising a machining opening for machining the mounting surface. A pulley for rotating a belt for driving the second wrist element or the third wrist element is fixed to the rotation shaft of at least one of the drive motors,
The position of the drive motor can be adjusted in a direction to change the tension applied to the belt along the attachment surface, and the drive motor is driven via the machining opening formed on the same side wall as the attachment surface. The robot wrist structure according to claim 6, further comprising an interface to which a position adjusting jig can be attached to the motor.

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